This thread is about in car non-disassembled engines that will not be cleaned internally.

I am doing my normal do diligence on a repair, head gaskets, and I came across a very interesting thing I did not know. According to the internet in many many conversations, Scotch brite and Roloc products contain aluminum oxide particles which destroy engine bearings (they can also have silica). This lead me on a chase to see if it was true and/or a safe product other than plastic razor blades. This may very well be one of those "not again" threads. However, when you are getting ready to clean the deck on your block for head gaskets, no question is off limits. I have read of those that do and don't use those products. I have see video after video of "my choice". I saw one mechanic at a ford dealership that used heavy thick steel wire wheels in a grinder to clean them. I also need / want to get the carbon off the pistons (smart or stupid?). If you have done this task, please let me know your thoughts. What did you use. Has any engine ever actually been destroyed from aluminum oxide particles? Do all of those different color pads have them? Is there a product especially for block decks?? If not, it seems like a good one to create. What about chemicals ? What about sand paper, but it has a "grit" as well?? I checked several MSDS PDF's and aluminum oxide was in some of the pads.

@IHBD This should be right up your alley.

Thanks
Donny

 

When I replaced my cylinder heads, I used green scotch-brite pads and PB Blaster to clean the deck and remove the carbon from the pistons. I honestly haven't heard that scotch-brites might be damaging to bearings, but I haven't had an issue. I dried the cylinders carefully after I was done, and changed the oil before starting the engine (and changed it again after running it for a few minutes), to clean out any PB Blaster/carbon/anything else that might have gotten in it while I was cleaning.

Personally, I would go for it and clean it with scotch-brites. They work well but aren't coarse enough to really scratch or damage anything. It just takes patience and a lot of elbow grease. I would imagine using it on the pistons/deck would be sealed off from any bearings, and if any potentially harmful substance does get in the crankcase it would be such a small amount it wouldn't do much.

I'm afraid I have little experience and cannot be as helpful as I'd like to, but this is what I did and it worked out for me with no issues.

 

The biggest problem with Rolocs and such is that they usually damage the gasket surface. It's not necessary to make it shiny, it's necessary to remove the old gasket material. Wire brushes also shed wires that get into things.

A scraper or single edge razor blade will work fine. If you use a razor, touching the corners with a file or a grinder to round them so they can't dig in and scratch is a good idea.

Permatex used to make a product called gasket remover that could be sprayed on and would dissolve adhesives and printed sealant on gaskets. It would also dissolve carbon. It's probably also been banned by now. Unless the carbon buildup is heavy it's probably not worth the effort. You could brind the pistons to TDC and scrape them then use a vac to get anything out of the crown area of the bore. We used to use Zip Strip paint remover gel that worked similarly to the gasket remover. If you do that, use it sparingly so it doesn't get into the rings, and wipe the bores with an oily rag when you're done.

 

ive done a few head gaskets so not overly experienced. 2 small blocks and one cummins 5.9. both cases, only a razor blade, vertically held in a scratching motion —not a peeling— were used.

halfway through my last job, the best gasket removal tool EVER arrived in the mail. tungsten carbide tip scraper, leaves no scrateches, beautifully easy. It is SSSOOOOO good.

link:

 

Agree^^^^, the tungsten carbide scrapers are the ****!!!! They're spendy, but once you use one, you'll wonder why you haven't heard of one before or haven't had one for years!!!! It's all you really need for the deck surface, besides a final wipe down with carb cleaner, rubbing alcohol, etc...before laying down the head gaskets. I like to use the scraper in one hand and the shop vacuum nozzle in the other while scraping. Either drain the block of antifreeze or be very careful around the water jackets with the shop vacuum! As far the piston tops, I highly recommend that you DO NOT USE anything sharp that is metal!!! Valve reliefs, edges and the whole top in general get nicked very easily....this will create a "hot spot" when running. Try the points of plastic interior panel remover tools in tandem with wiping it down with carb cleaner, injector cleaner, etc....if you have to use something harder, grab your smaller, most used, rounded tip flat-screw driver and gently "scratch" it off with the lightest pressure necessary! Disposable microfiber towels for the whole project. Good luck👍

 

my 2-cents -- i've done a few head gasket cleanings, and for the most part, i use a standard gasket scraper for bulk removal and finish the details with a straight edge razor blade. i do use a shop-vac in close proximity to suck in as much as possible. can't say i've ever had issues. i do remove the carbon from the piston tops - pretty much the same technique, but a smaller scraper (basically a modified laboratory spatula) and shop-vac. i pretty much avoid, scotch-bright, wire wheels, or any of these high-tech cleaning wheels. IMO, the key is the shop-vac.

 

certainly agree on the shop vac!

I have a big 90degree straight edge that i use to check for head flatness too. a simple feeler gauge trying to slide between it and the block.

I once had a block that was slightly over the published tolerance for the cast iron heads. grabbed a piece of granite,spray glue, 200 sandpaper, and decked them myself. it was awesome.

recently i experimented with the spray “copper coat” on my 5.9 cummins. It had the usual external water leak front passenger corner near the tstat. Cleaned it all up with the tungsten (takes zero pressure, amazing tool really) and coper coat sprayed the replacement gasket. worked great!

On my sbc’s ive not used the copper coat and probably will not.

edit, actually Joe C it was YOUR published valve lash adjustment I used! I used the feeler gauge and followed your procedure. It was so good i printed it for the “archives”. i added “oil film to the feeler gauge”. 👍

 

I've built lots of engines in my life. I've also changed my fair share of head gaskets. So for me what product I use changes based on the situation. You of course want to use the best tool for the job. Now "best" is subjective.

If the motor is out of the car and you are cleaning up a block for a rebuild then scothbright pads on a right angle die grinder are wonderful. I use the less course versions. This of course is for on iron blocks only. I try and not use rotary tools on aluminum. So I'll use the scotch bright rotary disk and clean the deck and use compressed air to blow out any debris. They work great

Now on aluminum it's a little different. I take a long flat sanding pad. Like what you would use to block sand a car before paint. I use 400 grit sandpaper with lots of WD40 and sand it clean. I then use brake cleaner to spray down the block. This method can also work on the mating surface of the cylinder head. It's not the right way. But it works as long as the head isn't warped.

Now if the engine is in the car and you're just changing a head gasket I like the single edge razor blades and a shop vac. It's a little slow but works well. This is for the block side. For the head I use 400 grip paper like I said before. A lot of times I'll use diechem and a large piece of glass with sandpaper taped to it to check the flatness of the head. I always try and avoid sending parts off to machine shop hell. I would rather go to the junkyard and pick up another head than send one off. In my area anyway getting another head is way cheaper. But I'm LS swapped so that part may be a little different for me.

Wire wheels work great in cleaning up the other surfaces of the head and block. Use this in a drill not anything high speed. These work well to clean up exhaust manifold and intake manifold mating surfaces. But I wouldn't use these on a block that is still in the car. The wires come off and could be an issue.

 

Thanks all, a carbide scraper (used gently at low angles) and razor blades will be it.

@Phobos84 ""I always try and avoid sending parts off to machine shop hell""

I have tried to find an old school machine shop in my area and I am having difficulty.

 

So if you're doing this inside the engine bay with a partially assembled engine, yes you're correct, the contaminants are absolutely an issue, and scotch-brite pad type products are terrible at producing very abrasive dust. Take steps to avoid contamination, using lightweight grease on the exposed cylinder walls and thick layer between the pistons and cylinder walls, which can be carefully wiped away later... clean rags covering lifter valley, tape odd any areas you can. Really like that Lyle carbide scraper myself, that's a great recommendation.

I also do something that I think most people don't do, I take a large flat very fine file, and use it to find and knock down high spots. But you have to handle it very carefully, and this doesn't work on warped components of course. On sealing surface of cylinder heads and intakes it works very well. Not sure I would recommend using this on a block installed in the car for the same reasons you mentioned about abrasives.

 

one other thing i do is tape a wad of paper towel in each cylinder. tape to the inside wall of the cyl and then papertowel to fill the hole. with the vacuum. debris cant get into the cyls then. Also stuff paper towels into the lifter valley. i sacrifice paper towel rather than a synthetic shop rag because i dont want synthetic fibers getting into the engine whereas the lapertowel bits would probably break down.

 

I had a problem with lint from cheap amazon red shop rags last time, I no longer trust them except wiping down individual parts that are to be blown off.

 

Dont believe ‘Bob-the-oil-guy’

Scotch-brite works great for cleaning engine deck surface prior to head gasket install (after you have used razor blades to scrape off the old material and carbon off the piston tops ! (Be careful not to knick them, but i used razor blades to clean the piston tops)

Bob-the-oil-guy assumes backyard mechanics are sloppy, messy, guys and cant keep the scotch-brite rinse residues out of the engine bores.

however it is entirely possible to do so if careful.
I found some craft lids that were the exact 4” bore size to completely mask off all 8 cylinder holes.

lastly, even if you did get some scotch-brite residues into the bores…you could simply spray some cleaner into there and suck it all out- provided you didnt rotate the engine crank.

where you need to be careful is the head holes into the water jacket. People thread chase those and spray brake cleaner into those - which is great.

but be sure to pull your knock sensors and drain out all that brake cleaner ! Otherwise it will eat your hoses from the inside out